The objective of the studies proposed is to investigate in detail the relationship between chemotaxis and lysosomal enzyme release and electrolyte transport in neutrophils, and, in particular, to directly test the hypothesis that changes of membrane cation transport properties are involved in the chemotactic response and lysosomal enzyme release of neutrophils. Using rapid sampling methods, we first propose to delineate the nature of these changes in transport properties and then to obtain evidence that they are involved in the response of neutrophils to chemotactic factors. After this has been done, we propose to attempt to understand how the chemotactic factors induce these changes in transport properties. To this end to study the effect of chemotactic factors on the activity of membrane-bound ATPase, the changes in the level of the intracellular exchangeable Ca ion2 po l and the membrane potential.